Physics are not simulated past a certain frame?
The problem you are having is not with timeline, but with the length of the rigid body cache.

The physics systems have cache length settings independent of the scene frame range, so you must ensure that they are set accordingly as well as setting the frame range. 

To do this for rigid bodies, set the End frame of the cache in Properties > Scene > Rigid Body Cache to the last frame you want the rigid bodies to be animated:



For 2.8 The Cache settings are under Rigid Body World> Cache



If you Baked the simulation (rather than just playing the scene animation to make a temporary cache of the simulation), press Free Bake in Properties > Scene > Rigid Body Cache to remove and "unlock" that cache: